[Flowers]

The radiator fans are now working but when the sensor is unplugged I assumed the fans would become active.

I have the t series engine which I think has two sensors? One on the thermostat and one at the side of the radiator?

Is this normal behaviour?

[RoverTD]

I think the sender makes the circuit when the coolant gets too hot, which activates the fans, so disconnecting it leaves them switched off.

[Flowers]

I think the sender makes the circuit when the coolant gets too hot, which activates the fans, so disconnecting it leaves them switched off.

Interesting! I thought so many resources online say the opposite. Is anyone else able to confirm this

[crepello]

The one on the radiator will be a simple bi-metallic switch, which will close at
the temperature stamped on its body (not that you can see this once installed).
So if you want to test the wiring to the fan, you can unplug the loom from the
radiator switch and short across the plug pins - But DO first make sure nothing is
going to catch in the fan!